The sigma also seems to demonstrate slightly less magnification (is sigma a short 35 or nikon a long 35?)

Do you see that at infinity focus or only at closer distances? Most lenses these days change focal length as they focus closer, and the amount of change varies a lot. I'd expect the lenses to be nearly identical at infinity focus.

-- hide signature --

Leonard Migliore

Good point, this was quick test at close distances of 2 to about 5 meters, reason likely as you state the issue. DWR